不同提取方法所得褐藻糖胶的理化性质比较

通过各种理化性质的测定,对不同提取方法所得褐藻糖胶进行了分析,乙醇沉淀法的测定结果为:总糖含量(76.00±9.00)%、硫酸根含量(11.33±0.47)%、岩藻糖含量(35.60±4.20)%、重均/数均分子量(3.42×104)/(1.21×104);高分子电解质沉淀法的测定结果为:总糖含量(70.00±11.00)%、硫酸根含量(10.80±0.58)%、岩藻糖含量(35.15±2.85)%、重均/数均分子量(1.15×105)/(5.88×104)。高分子电解质沉淀法所得褐藻糖胶粗品和纯化后褐藻糖胶,其高分子电解质残留量分别为(0.12±0.038)%和(0.022±0.002)%。结果表明,乙醇沉淀法所得产品质量优于高分子电解质沉淀法,但是高分子电解质沉淀法具有工艺简单、成本低,更适于工业化生产等优点。     

27Al核磁共振波谱法测定环境生物样品中铝研究进展

近二十年来,高分辨率 27Al核磁共振（ 27Al NMR）广泛应用于研究 Al?离子水解过程 ,Al?与环境生物配体的配位化学 ,环境与生物样品中铝含量测定和形态分析 ,监测铝在植物、动物、酵母菌等微生物中的转运过程 ,具有快速、直接、非破坏性等优点。 27Al NMR不仅适用于高浓度的溶液,也可应用于低浓度 (10－ 6mol· L－ 1)的实际环境、生物样品。应用 27Al MAS NMR可直接对固态样品中铝的存在状态和含量进行表征和测量。本文中对 27Al NMR的应用进展作一评述,并总结了近二十年来文献发表的 27Al化学位移数据。引用文献 70余篇。     

Synthesis,Structure and Spectral Properties of a Novel Triaryl Substituted Triazole and Its Co(Ⅱ) Complex

The new compound 3-(2-pyridyl)-4-(p-methoxyphenyl)-5-(2-thienyl)-1,2,4-triazole L was synthesized and characterized by elemental analysis,IR,1H NMR,13C NMR,MS,UV and photoluminescent spectra.The complex CoL2(NCS)2 was prepared by the reaction of ligand L with Co(SCN)2,and its structure was characterized by single-crystal X-ray diffraction,IR,UV,elemental analysis and MS.The complex crystallizes in monoclinic,space group P21/n with a=13.7639(19),b=7.6641(11),c=18.409(3),β=101.549(3)o,V = 1902.6(5) 3,Z=2,C38H28CoN10O2S4,Mr=843.87,Dc=1.473 g/cm3,μ=0.720 mm-1,S=1.075,F(000)=866.0,the final R=0.0825 and wR=0.2149 for 2566 observed reflections(I2σ(I)).In the crystal structure,the cobalt atom adopts a distorted octahedral environment with two NCS-ions in the axial positions and two bidentate chelating L ligands in the equatorial plane.The extended 2D network of the complex is formed by intermolecular C-H…N hydrogen bonds together with π-π stacking interactions.     

CoAu2(CN)4(NITpPy)2(H2O)2]n: a new 2-D interdigitating complex containing dicyanoaurate(I) anion, a radical, and cobalt(II) ion incorporating gold...gold and hydrogen bonding interactions

A novel complex, [[CoAu2(CN)4(NITpPy)2(H2O)2]]n, 1, containing the cobalt(II) ion, dicyanoaurate(I) anion, and nitronyl nitroxide radical building blocks, has been prepared and structurally characterized by single-crystal X-ray analysis. The structure of complex 1 illustrates that aurophilicity and hydrogen bonding interactions increase dimensionality, generating a 2-D interdigitating system. The spectroscopic and magnetic properties have been investigated.     

Photochemical reactions of 2-bromotropone and 2,7-dibromotropone with 9,10-dicyanoanthracene

The photochemical reactions of 2-bromotropone and 2,7-dibromotropone with 9,10-dicyanoanthracene gave products with anthracene, anthracenone, and dihydroanthracene skeletons both in polar and non-polar solvents. These products were formed by attack of water contaminated in the solvent, by attack of the troponoid, and by attack of the solvent used in the reactions, respectively, on a reaction intermediate. In a mixed solvent of benzene and methanol, a benzaldehyde derivative with a tribenzo-2-oxabicyclo[3.2.2]nonane system was obtained. This result was informative about the reaction mechanism, and suggested the formation of an [8 + 4]pi cycloadduct with a tribenzo-2-oxabicyclo[3.2.2]nonane system between the troponoid as the 8 pi component and the 9,10-dicyanoanthracene as the 4 pi component. In non-polar benzene, a new tetrabromodihydroanthracene derivative was obtained together with anthracenone and anthracene derivatives. It was proved by the reaction in benzene-d6 that the new product was formed by attack of benzene-d6.     

几种微分示波伏安曲线理论方程的推导

推导了适用于由单电解池和双电解池所获得的微分示波伏安曲线方程,从理论上描述了i'_f和i″_f的示波图象。     

A Survey of Aluminum Speciation in the Forest-Well Drainage Water from the Rhode River Watershed

In the Chesapeake Bay Region, acidic atmospheric deposition has deleterious effects on watershed and freshwater ecosystems. One of the associated effects is the disappearance of fish from the streams.     

Eu2(p-ClC6H4COO)6(C12H8N2)2配合物热分解机理及非等温动力学

The thermal decomposition behaviour of europium p-chlorobenzoate complex with 1, 10-phenanthroline and its kinetics were studied in nitrogen by non-isothermal thermogravimetry.Its thermal decomposition occurs mainly in three steps..The intermediate and residue for each step of decomposition were identified from TGcurve.The kinetic parameters were obtained from analysis of the TG-DTG curves by the Achar method.the Madhusudanan- Krishnan-Niman (MKN) method and Ozawa method respectively.The most probable mechanisms function for the first and second stage were suggested by comparing the kinetic parameters.     

Determination of fluorescent whitening agents in environmental waters by solid-phase extraction and ion pair liquid chromatography-tandem mass spectrometry

A comprehensive method for the trace determination of four stilbene-type disulfonate and one distyrylbiphenyl-type fluorescent whitening agents (FWAs) in environmental water samples was developed and validated. Various solid-phase extraction (SPE) cartridges were investigated. The newly developed Oasis WAX (weak mixed-mode anion exchange and reversed-phase sorbent) SPE cartridge provides the optimal sample extraction results. The analytes were then identified and quantitated by liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS-MS) in negative ionization mode, applying di-n-hexylammonium acetate (DHAA) as the ion-pairing reagent in mobile phase. Limits of quantitation (LOQs) were established between 4 and 18 ng/l in 50 ml of water samples. Intrabatch and interbatch precision with their accuracy at two concentration levels were also investigated. Precision for these five FWAs, as indicated by RSD, proved to be less than 13 and 11%, respectively, for intra- and interbatch. Accuracy, expressed as the mean recovery, was between 68 and 97%. The method was finally applied to environmental water samples, showing the occurrence of five FWAs in both river water and wastewater treatment plant (WWTP) effluent samples.     

流动注射编结反应器在线分离富集技术在原子光谱中的应用

综述了流动注射编结反应器在线富集技术在原子光谱中的研究进展,重点突出编结反应器富集的相关机理和不同富集方式的实际分析应用,并对流动注射编结反应器富集分离的应用前景进行了展望。引用文献59篇。